Manufacture of fibers from thermoplastic materials such as glass



July 11,1961 1 M. LEVECQUE ETAL 2,991,507

MANUFACTURE OF FIBERS FROM THERMOPLASTIC MATERIALS SUCH As GLASS Filed July 8, 1957 L T N5) Z 7 q a g w M E E\ 5 N 3 'v NTORS IN E LI ATTORNEY United States Patent 2,991,5'07 MANUFACTURE OF FIBERS FROM THERMO- PLASTIC MATERIALS SUCH AS GLASS Marcel Levecque, Saint-Gratien, and Maurice Chal'pentier, Rantigny, France, assignors to Societe Anonyme des Manufactures des Glaces et Produits Chimiques de Saint-Gobain, 'Chauny & Cirey, Paris, France, a

corporation of France Filed July 8, 1957, Ser. No. 670,612 Claims priority, application France July 12, 1956 2 Claims. (Cl. 1847.3)

The present invention relates to the manufacture of fibers from thermoplastic materials in the viscous state, especially glass fibers.

According to the work of the applicants, it is already known, in order to produce fibers of great fineness, to submit the material in the form of filaments, which is projected by the action of centrifugal force from a revolving body, such as a hollow body having one or several rows of orifices on its periphery, to the action of gaseous currents beyond the rotating body.

It is the object of the present invention to transform the melted thermoplastic material into filaments which are projected from a plurality of superposed rows of orifices in the peripheral wall of a rapidly revolving body, such as a hollow centrifuge. These filaments issuing from the superposed rows of orifices by centrifugal force are subjected to the action of jets of hot fluid, directed transversely with respect to the planes of emission of the filaments. The velocity of the jets is of such a value that the filaments emitted through the rows of orifices nearest the gas jet openings are drawn along by these jets without crossing them, but in the case of the damping of these jets along the depth of the peripheral wall, the filaments emitted from the more distant rows of orifices from the gas jet openings, cross these jets.

This dilference in the order of things or behavior has a consequence that the filaments emitted by the firstmentioned rows of orifices are violently attacked by the fluid jets and are transformed into very fine fibers. On the other hand, the filaments issuing from the other rows of orifices undergo an action which is much less violent and are transformed into fibers which are generally much coarser.

According to the invention, the threads of melted material can be submitted, after leaving the hot zone of gaseous currents, to the action of blown air currents which carry along the formed fibers to lead them onto a reception medium preventing their becoming entangled.

The invention permits the production of mixtures of fine fibers and fibers of a greater diameter whose proportion can be variable and regulated at will. The proportion of these two types of fibers can be regulated by varying, according to any convenient means, the number of rows of orifices which are submitted to each of the two types of attack of fluid jets described above.

The fibers having crossed the jets of hot fluid may attain a relatively long length. The products constituted by such mixtures have good insulation properties by virtue of the presence of very fine fibers, and good elasticity due to the long fibers.

In accordance with the invention, the order of speed of gaseous currents can be varied to a large extent by regulation of the delivery of the fluid being used. Where a combustion chamber is used to produce the gaseous currents, the supply of fuel or air to this chamber may be regulated, and/ or the expansion orifices of this chamber may be regulated by varying the dimension of these orifices or their selection. For this purpose a combustion chamber with one or several discharge orifices of variable size may be used.

. 2,991,507. Patented July) 1,, 1961 The attached drawing represents, by way of example, a few embodiments of the invention, wherein FIG. lis ,a cross-section of a preferred embodiment; and

FIG. 2 illustrates a diflerent embodiment of the combustion chamber which permits regulation of the fuel or air introduced thereinto.

The centrifugal body is represented by -1. This body, which rotates at great speed about its axis, for example at a speed of approximately 3,000 r.p.m. or more, has a cylindrical peripheral wall provided with two to twenty rows of projection orifices 2 of a suitable diameter through which the melted material fed into the interior of the centrifuge -1 is projected. A combustion chamber 3 of generally annular form is disposed around the centrifuge 1, permitting combustion gases at great speed and high temperature to be directed through the discharge orifice 4. These gases are directed along the length of the peripheral wall of the centrifuge and transversely to the horizontal planes of emission of the filaments. In addition, concentrically to the centrifuge, is placed a crown 5 provided at its lower part with an annular hole 6 through which the current of gas is blown.

The speed of the gases leaving chamber 3 is regulated so that the filaments 7 escaping from the upper rows of orifices of the centrifuge do not cross the current of gas from discharge orifice 4 of the combustion chamber 3 while the filaments 8 escaping from the lower rows cross this current in consequence of the lowering of the force of this gas stream following its traverse past the upper rows of orifices. The filaments 7 undergo an abrupt change in direction through the action of this gas current and are drawn out into very fine fibers. The filaments 8, strongly heated by their passage through the hot gas current, are subjected to the action of the gas current blown through orifice 6 and are drawn out into thicker fibers.

In FIG. 2 the combustion chamber 3, provided with annular expansion orifice 4, is fed with fuel and air by means of conduits 11 and 12, the supply of which may be regulated by means of valves '11 and 12' in the respective conduits. The speed of the gaseous currents emanating from the expansion orifice 4 may be varied by regulating the delivery of the fuel and/or air by means of these valves 11' and 12.

By way of example, according to the invention linings or sheets may be obtained made up of a mixture of very fine fibers of less than 3 microns diameter and of fibers from 6 to 10 microns diameter in a proportion which may be regulated as desired.

We claim:

1. A method of manufacturing fibers from heated viscous material which includes the steps of applying centrifugal forces to a body of heated viscous material to form the material into a plurality of annular rows of filaments at different planes, and deriving fibers of difierent characteristics from the filaments occupying said planes by establishing a source of and directing substantially vertically a ring-like blast of hot gases transversely to the planes of the filaments at such an intensity as to divert and draw out the filaments occupying the planes in proximity to the source of the blast into fine fibers without crossing the blast, while the blast traversing the filaments in the planes remote from the source of the blast is of a diminished intensity to enable the last-mentioned filaments to cross the blast as coarse fibers, and directing an annular blast of air on said coarse fibers to entrain, draw out and convey them to a disposition point without tangling.

2. The method defined in claim 1, including the step of controlling the relative numbers of rows of filaments crossing and notcrossing the annular blast of hot gases 2,395,371 Dockerty Feb. 19, 1946 by regulating the heat and force of said blast. 2,489,243 Stalego Nov. 22, 1949 2,609,566 Slayter et a1. Sept. 9, 1952 References Cited in 'the file of this patent 2,863,493 Snow et a1. Dec. 9, 1958 V UNITED STATES PATENTS 5 FOREIGN PATENTS 2,270,223 Schlaek Jan. 13, 1942 202,877 Australia July 5, 1956 

